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Quarter 3
LESSON: Produce Vegetables
Module 5: Maintain the Growth of Vegetable Crops
- Apply recommended kind and rate of fertilizers
- Perform irrigation and drainage practices
- Practice weeding and cultivation
- Control insect pests and diseases
- Perform mulching
Content Standard Performance Standard The learner demonstrates understanding in maintaining the growth of plants.
The learner independently maintains the growth of plants according to the approved practices as specified in the Vegetable Production Manual (VPM).
Introduction
This module deals with the knowledge, skills, and attitudes in applying the recommended kind and rate of fertilizer, performing irrigation and drainage, weeding and cultivating, controlling insect pests and diseases, and mulching.
Learning Competencies/Objectives
This lesson has the following learning competencies/objectives:
- Kinds and rate of fertilizers
- Plant food elements
- Nutrient content of inorganic fertilizer
Lesson 1 Kind and Rate of FertilizersApplying Recommended
- Fertilizer computation
- Fertilizer application
- Loss of nutrients from the soil
- Methods of conserving soil fertility
- Composting
Directions: Read and understand the questions carefully. Write the letter of the correct answer in your test notebook.
- Plants need food to nourish their parts. Which refers to any organic or inorganic materials of natural or synthetic origin which is added to the soil to suppy certain elements essential for plant growth? a. Fertilizers b. Trace elements c. Macroelements d. Microelements
- The amount of fertilizer to be applied depends on many factors. Which is the least observed factor regarding the rate of fertilizer application? a. Nutrient requirement of the plant b. The manner of applying the fertilizer c. Environmental factors particularly rainfall d. The capability of the farmer to supply the neededfertilizer material
- Which method of fertilizer application is most applicable to seedlings for their starter solution? a. Fertigation b. Broadcasting c. Foliar application
Diagnostic/Pre-assessment
- Which fertilizer element hastens maturity, stimulates blooming, aids in seed formation, and gives plants hardiness? a. Calcium b. Nitrogen c. Phosphorus d. Potassium
- Which is not true about organic fertilizers? Organic fertilizers... a. Decomposed farm manures b. Improve soil physical conditions c. Facilitate soil erosion d. Retain soil humidity
Activity 1
Human beings, animals, and plants need a lot of things in order to live. These three living things have symbiotic relationships. The absence of one will make life miserable.
The way humans, animals, and plants live differ from one another. Let us find out how they live. Group yourselves into four for the following topics to discuss. Discuss among yourselves, summarize your ideas, and then present your output to the class for further discussion.
Group 1 – How do human beings maintain a healthy life?
Group 2 – How do animals live?
Group 3 – How do plants complete their life cycle?
KNOW
Group 4 – What is the symbiotic relationship of humans, animals, and plants like?
Reading Resources and Instructional Activities
Apply Recommended Kind and Rate of Fertilizers
Plant food. Plants and animals require food for growth and development. This food is composed of certain chemical elements often referred to as plant-food elements.
Table 7. Plant food elements and their functions (Mcvickar 1970)
Macro- Elements
Plant Nutrient
Chemical Symbol
Functions
Nitrogen N Promotes dark green color; leaf, stem, and fruit development; and hastens growth and increases the protein content of the crop. Phosphorous P 2 O 5 Favors rapid plant growth and development; hastens fruiting and maturity; and improves the quality of the crop. Potasium K 2 O Hastens maturity; stimulates blooming; aids in seed formation; and gives plants hardiness. Calcium Ca Corrects acidity; acts as protective sieve for the nitrates to set through in passing into the cells; and acts as a cement between the walls of the cells to hold them together. Magnesium Mg The key element in the
Plant food refers to the necessary materials which a plant uses so it can build new tissues and, at the same time, carry on its normal functions.
According to Mcvickar (1970), fertilizer is any manufactured or processed material or mixture of materials that contains one or more of the recognized plant-food elements, in liquid or dry form.
On the other hand, INGO (2005), claimed that a fertilizer is any organic or inorganic material of natural or synthetic origin, which is added to the soil to supply certain elements essential to plant growth. Fertilizers are used to increase the growth rate, yield, and quality or nutritive value of plants. The manual explained further that for many decades in the past, the term fertilizers practically meant commercial fertilizers of non-living origin. In recent years, however, increasing attention has been focused on organic and bio- fertilizers that are biological sources of plant nutrients.
The proper usage of fertilizers requires knowledge not only of their properties but also of their effects on soil. The amount of fertilizer to be applied depends on many factors, which include the nutrient requirement of the plants, the ability of the soil to supply nutrients, yield potential, other management practices, the capability of the farmer, and other environmental factors particularly rainfall.
Kinds of fertilizer
1. Organic fertilizers are farm manures, compost, crop residues, and other farm wastes, which supply nutrients and improve soil physical conditions. Organic fertilizer is generally the most valuable soil conditioner. As soil conditioners, organic fertilizer helps prevent soil erosion, crushing, and cracking of soil. They retain soil humidity and improve the internal drainage of the soil. These fertilizers should serve as supplement to inorganic fertilizers. These improve the physical make-up of the soil making the soil porous and rich in organic matter as explained by
Sangatan and Sangatan (2000). Again, Sangatan and Sangatan (2000) enumerated the sources of organic fertilizer as follows: Animal wastes: cattle, carabao, pig, goat, poultry, and horse manure or urine, etc. Crop wastes: rice straw, corn stalks, weeds, stubbles, plant leaves, husks, etc. Human inhabitation wastes: night soil, sewage, and garbage Green manure: ipil-ipil leaves, legumes, and madre de cacao leaves Water crops or plants: water hyacinth (water lily), water alligator, and water lettuce Biological organic sources: azolla, and blue green algae Silt, river mud, and pond mud By-product of biogas digester, digested sludge, and effluent Other sources: animal bone, ash, seaweeds, and guano (bat manure)
2. Inorganic (chemical) fertilizers) usually result from chemical processes such as sulfuric acid treatment or rock phosphate to produce superphosphate. It consists of materials processed or transformed into a chemical material or fertilizer. Types of fertilizer based on the fertilizer element present 1. Single element fertilizer contains only one of the major fertilizer elements. Examples: Ammonium sulfate, urea, and superphosphate 2. Incomplete fertilizer contains only two major elements like ammophos (nitrogen and phosphorus). 3. Complete fertilizer contains the three primary plant food elements: nitrogen, phosphorus, and potassium.
available N but it does not contain P 2 O 5 and K 2 O, therefore the remaining 79 kg represents the materials termed as ”carriers” or “fillers”. A mixed complete fertilizer with a grade of 12-24-12 contains 12%N, 24% available P 2 O5 ,and 12% K 2 O, respectively.
The fertilizer recommendation is expressed in kilograms N, kilograms P 2 O 5 and kilograms K 2 O per hectare, respectively. In technical publications, this is written as, 90-60-30. This recommendation involves the application of 90 kg N, 60 kg P 2 O 5 and 30 kgK 2 O 5 per hectare, respectively.
To calculate the weight of fertilizer, divide the recommended rate by the nutrient content of the fertilizer material (from the grade or analysis). Thus:
(1) Weight of fertilizer material=
To get the number of fertilizer bags, divide the weight of nutrients required by the weight of the nutrients per bag, thus:
(2) Number of fertilizer bag =
Or, divide the weight of fertilizer from formula (1) by the weight per bag, thus, Number of fertilizer bag =
Sample Computations:
a. Recommended rate: 90-60-30 NPK/ha
Available Fertilizer Materials: a. Urea (46-0-0) b. Ordinary Superphosphate (0-20-0) c. Muriate of Potash (0-0-60)
General Formula:
Weight of Fertilizer Material (FM) = Weight % Nutrientof Nutrient X 100
Step 1. Weight of Urea = or.^9046
= 195.65 kg
Step 2. Weight of OSP = or.^6020
= 300 kg
Step 3. Weight of MP = or.^3060
= 50 kg
b. Recommended Rate: 90-60-30 kg NPK/ha
Available Fertilizer Materials: a. Ammonium phosphate (Ammophos) (16-20-0) b. Ammonium sulfate (21-0-0) c. Muriate of potash (0-0-60)
Step 1.
Weight of Ammophos =^6020 x^100
= 300 kg Note: since ammophos contains two elements, nitrogen (16%N) and phosphorous (20%P 2 O 5 ) therefore, we already satisfied the 60 kg requirement for P 2 O 5 and another 60 kg for nitrogen. Again, since the recommended rate for N is 90 kg/ha therefore, we have not satisfied
From this 428.57kg of complete fertilizer, 60kg each of nitrogen (N), phosphorus (P 2 O 5 ) and potassium (K 2 O) were already satisfied. However, the recommendation for nitrogen is 100 kg, therefore, it is short of 40kg. This remaining amount will be supplied by urea which contains 46% nitrogen. Step 2. Compute the remaining amount of 40kg nitrogen which will be taken from Urea (46-0-0).
Weight of Urea =
= 86.96 kg
Methods of fertilizer application
Villegas and Malixi (1977) stated that to get the maximum benefit, the fertilizer must be applied where the plant can readily absorb it. Proper placement of a fertilizer will provide an efficient and continuous supply of plant nutrient and will prevent salt injury to the seedlings. The following are the different methods of fertilizer application:
- Broadcast method. The fertilizer material is applied uniformly over the entire area before planting or while the crop is growing. Topdressing refers to broadcast application on growing crops. Uniform distribution of the fertilizer enables safe application of large quantities of fertilizer without injuring the crop. However, it may reduce fertilizer efficiency because of fertilizer fixation or by volatization.
- Localized application. The fertilizer is applied close to the seed or plant, either in band adjacent to the plant rows (side dressing) or by plow-sole application. In the plow-sole method, the fertilizer is covered lightly with soil before seeding or planting. Localized application is essential for high rate applications of high analysis fertilizers. This method is commonly used for most vegetables.
- Foliar application. Plant nutrients may be applied on the aerial part of the plant. The dissolved nutrient must penetrate the cuticle of the leaf or the stomata and then enter the plant cells. This method is usually employed only in applying micronutrients. Marginal leaf-burn could occur with the application of high concentrations of fertilizer.
- Applied with the seed – Fertilizer is broadcast together with the seeds or the seeds are coated with fertilizer by means of an adhesive such as cellofas or gum Arabic.
- Fertigation – This involves dissolving the fertilizer materials in water and then applying it with the use of a sprinkler.
Methods of determining soil fertility
Training Manual in Horticulture NC II (2007),lists the methods of determining soil fertility as follows:
1_._ Field fertilizer trials. As the term implies, field fertilizer trial experiment is carried out in the field. It could be conducted in different places under different seasons. When managed and conducted properly, the results obtained from this method are very reliable.
- Soil analysis. It is a rapid method of assessing the fertilizer needs of crops. The principle involved is that the amounts of available nutrients in the soil are directly related up to a critical point with the growth and yield of crop. Soil analysis consists of four phases namely:
- Proper collection of soil samples
- Chemical analysis
- Interpretation of analytical results
- Formulation of fertilizer recommendation
- Medium feeders consume not much of the essential plant food elements.
- Light feeders consume only a little amount of the plant food elements.
Loss of nutrients through surface run-off. Rain water or excess irrigation water which runs off the surface of the ground may carry not only soil particles and the food they contain but also the plant food which gets dissolved in the running water. Loss of nutrients through leaching. Even if we do not plant, the minerals in the soil may be lost by leaching, which is when the soluble substances go with the water that drains down to the lower depths of the soil beyond the reach of the roots. This is especially true in cases of sandy soil. Soil erosion. This is the greatest enemy of the farmer. Erosion is the removal of soil from the field through natural forces.
“Soil nutrients are lost through harvesting, leaching, prolonged wet weather, flooding, and de-nitrification. Sustainable agriculture involves returning nutrients to the soil in the form of green manure, crop residues, composted manure, and other wastes to improve and maintain soil life. During the growing season, plants fix carbon dioxide by photosynthesis. Around 20 to 25 percent of this fixed carbon is returned to the soil through plant roots.
Healthy soil consists of fungi, microbes, earthworms, macro fauna and micro/mesofauna. Sustainable agriculture involves not only the physical properties and mineral structure of the soil, but also the process by which organic matter is transformed into humus by microbes, fungi, earthworms etc. Incorporating crop residue and other organic matter into the soil
promotes microbial growth which in turn promotes humus production and soil fertility”. http://ecochem.com/trial_fvr_master.html
“A heavy rainstorm may splash as much as 90 tons of soil per acre. However, the majority of the soil splashed is not immediately lost from the field. Most of the splashed soil particles do not leave the field; they clog surface pores, which in turn reduce water infiltration, increases water runoff, and increases soil erosion”.http://www.extension.iastate.edu/CropNews/2008/0604MAlKaisiMHelmers.htm
Methods of conserving soil fertility Soil is one of the most important natural resources. We need to devise and implement ways of conserving soil.
Ways of conserving soil fertility according to http://www.buzzle.com/articles/10- ways-to-conserve-soil.html
- Plant trees : “Roots of trees firmly hold on to the soil. As trees grow tall, they also keep rooting deeper into the soil. As their roots spread deep into the layers of soil, they hold it tightly, thus preventing soil erosion. Soil under a vegetative cover is saved from erosion due to wind as this cover acts as a wind break.”
- Build terraces: “Terracing is a very good method of soil conservation. A terrace is a leveled section of a hilly cultivated area. Owing to its unique structure, it prevents rapid surface runoff of water. Terracing gives the landmass a stepped appearance, thus slowing the washing down of soil. Dry stonewalling is a method used to create terraces in which stone structures are made without using mortar for binding.”
- No-till farming (zero tillage): “The process of preparing soil for plowing is known as tilling. The process of tilling is beneficial in mixing fertilizers in the soil, making rows and preparing the surface for planting. But the tilling activity could lead to
and make the garden bed look more attractive. Organic mulches also help improve the soil’s fertility, as they decompose. http://gardening.about.com/od/gardenmaintenance/a/Mulch.htm
Organic Mulches and their Uses
“Bark mulches are best used around trees, shrubs and in garden beds where you won’t be doing a lot of digging, like front walkways and foundation plantings. These woody mulches don’t mix well into the soil and it can become a hassle to have to keep moving them aside to make way for new plants.” “Compost and Composted Manure can be used anywhere, as long as they are relatively well composted and weed free. You can use them as a coating of mulch or simply side dress plants with them during the growing season, to insulate and give a boost of slow released nutrients.” “Grass Clippings are a mixed bag and are best suited to remote areas of your garden where you basically want to suppress weeds. Grass clippings, like most green plant debris with high water content, decompose very rapidly and in the process they can get somewhat slimy, with an unpleasant odor - so use with discretion. Grass clippings also tend to mat down and not allow water to pass through. Ideally you should use a mulching mower and leave the clippings on the lawn to add fertility to that soil. However if you bag your grass clippings, don’t throw them away unless you have used weed killer or some other pesticide on your lawn. Synthetic lawn care products can be bad for some flowers and you certainly don’t want to use them in your vegetable garden. But untreated grass clippings can either be dumped into your compost bin or used to mulch open, unplanted areas.”
“Newspaper as mulch is becoming more and more popular. Most newspapers have switched over to organic dyes, especially for their black & white sections. Shredded newspapers have been used for years to keep plant roots moist while shipping. Layered sheets of newspaper also have
great moisture retention abilities and they act like other organic mulches as far as suppressing weeds and controlling soil temperatures. They are also great for smothering existing grass, to jump start a new garden bed. To use as mulch in the garden, spread a layer of 4 - 8 sheets of newspaper around the plants. Moisten the sheets to keep them in place. On windy days it’s easier to moisten the sheets before you place them down. Cover the newspaper with a 1-3 inch layer of another organic mulch and the weed protection should last throughout the growing season.”
“Shredded Leaves are nature’s favorite mulch. Shredded leaves can be used as mulch anywhere and have the added bonus of being free.” Straw and Salt Hay are popular mulches for the vegetable garden. They keep the soil and soil borne diseases from splashing up on lower plant leaves and make paths less muddy. Straw decomposes very slowly and will last the entire growing season. It also makes a nice home for spiders and other beneficial insects that will move in and help keep the pest population in control. And finally, it’s easy to either rake up or work into the soil when it’s time to plant a new crop or put the vegetable garden to bed. http://gardening Soil conservation is a set of management strategies for preventing the soil from being eroded or becoming chemically altered by overuse, acidification, salinization, or other chemical soil contamination. It is a component of environmental soil science. “There are conventional practices that farmers have used for centuries. These fall into two main categories: contour farming and terracing, There are many erosion control examples such as conservation tillage, crop rotation, and growing cover crops. Windbreaks are created by planting sufficiently dense rows of trees at the windward exposure of an agricultural field subject to wind erosion. ”http://en.wikipedia.org/wiki/Soil_conservation
